Process for compensating a phase and amplitude response between a multiphase setpoint and actual value and circuit for implementing the process

ABSTRACT

The invention relates to a process for compensating a phase and amplitude response between a multiphase setpoint and actual value (i Rw , i Sw , i Tw  and i Rx , i Sx , i Tx ), the first step being to determine the modulus setpoint value (|i w  |) or modulus actual value (|i x  |) and the angular setpoint value (ε w ) or angular actual value (ε x ) of the setpoint or actual value vector (i w  or i x ), a modulus manipulative variable (|i wxy  |) and an angular manipulative variable (ε wxy ) then being generated by modulus and phase from a modulus deviation (|i w  |-|i x  |) and an angular deviation (ε w  -ε x ) which are added by modulus and phase to the output quantities (|i w  |, ε w ) of the setpoint value vector computer (26), these modulus and phase sums (|i Kw  |,ε Kw ) being transformed into a multiphase, compensated setpoint value (i RKw , i.sub. SKw, i TKw ), and to a circuit arrangement for implementing the process. It is possible in this way for the phase and amplitude response to be compensated between a multiphase setpoint and actual value (i Rw , i Sw , i Tw  and i Rx , i Sx , i Tx ) although a phase and amplitude response depends on the response characteristic of a controlled system which is dependent on a disturbance variable (M z ).

BACKGROUND OF THE INVENTION

The invention relates to a process for compensating a phase andamplitude response between a multiphase setpoint and actual value andcircuit for implementing the process.

Specifying a command variable W, for example in accordance with a timingfunction W(t)=W sin (αt) on a known control loop consisting of setpointadjuster, comparator, controller, controlled system and measuringtransducer produces in the controlled variable a phase and amplitudeshift in relation to the command variable W. With increasing frequencyof the command variable W, the phase and amplitude response variesbetween setpoint and actual value. An undesired phase and amplituderesponse between setpoint and actual value is also produced in the caseof multiphase control loops. A multiphase control loop represents, forexample, a conventional current control for a three-phase current drivewith voltage-controlled convertor. The amplitude and phase of actualvalue can be measured or determined without distortion in thismultiphase control loop.

The phase and amplitude response is determined by the responsecharacteristic of the control loop. If this response characteristic isknown, the phase and amplitude response of the control loop can becompensated by a correction device in the command channel. If, bycontrast, the response characteristic of the controlled system is afunction of the disturbance variable or dependent on controlledvariables which are not known or cannot be measured, the said type ofphase and amplitude response can be compensated only insufficiently bymeans of a correction device in the command channel.

The textbook "Stromrichter zur Drehzahlsteuerung von Drehfeldmaschinen"(Static convertors for speed control of polyphase machines), Part III,Convertors, by Erich Eder, 1975, pages 102 to 111 discloses resolvers bymeans of which a two-phase system having two orthogonal currents isformed from a three-phase system. A current vector which rotates can beformed from these two orthogonal currents. The modulus of this currentvector and the rotary angle are formed by means of a C/P transformer(Cartesian/polar).

SUMMARY OF THE INVENTION

It is the object of the invention to specify a process for compensatinga phase and amplitude response between a multiphase setpoint and actualvalue, the phase and amplitude response being produced by a responsecharacteristic of a controlled system which depends on a disturbancevariable, and a circuit arrangement for implementing this processaccording to the invention.

This object is attained by a process for compensating a phase andamplitude response between a multiphase setpoint and an actual value(i_(Rw), i_(Sw), i_(Tw) and i_(Rx), i_(Sx), i_(Tx)) consisting of thefollowing steps:

a) determination of a modulus setpoint value (|i_(w) |) and a rotaryangular setpoint value (ε_(w)) of a setpoint value vector (i_(w)) formedfrom the multiphase setpoint value (i_(Rw), i_(Sw), i_(Tw)),

b) determination of a modulus actual value (|i_(x) |) and a rotaryangular actual value (ε_(x)) of an actual value vector (i_(x)) formedfrom the multiphase actual value (i_(Rx), i_(Sx), i_(Tx)),

c) comparison of the modulus setpoint value (|i_(w) |) with the modulusactual value (|i_(w) |) from whose modulus differential value (|i_(w)|)-|i_(x) |) there is generated a modulus manipulated variable (|i_(wxy)|) which when added to the modulus setpoint value (|i_(w) |) produces acompensating modulus setpoint value (|i.sub._(K) ^(w) |),

d) comparison of the rotary angular setpoint value (ε_(w)) with therotary angular actual value (ε_(x)) from whose angular differentialvalue (ε_(w) -ε_(x)) there is generated an angular setpoint value(ε_(wxy)) which when added to the angular setpoint value (ε_(w))produces a compensating angular setpoint value (ε_(Kw)),

e) determination of a multiphase compensating setpoint value (i_(RKw),i_(SKw) i_(TKw)) of the compensating setpoint value vector (i) formedfrom the compensating modulus setpoint value (|i_(K) ^(w) |), and thecompensating rotary angular setpoint value (ε_(Kw)).

The modulus and the rotary angle of the setpoint and actual value vectorformed from the multiphase setpoint and actual value is firstlydetermined by this method, it then being possible to determine a systemdeviation separately for the modulus and the phase. This modulusdifferential value or this angular differential value is added to themodulus setpoint value or the angular setpoint value of the setpointvalue vector. The compensating setpoint value vector thus determined,which is present as modulus and rotary angle, is transformed into amultiphase compensating setpoint value. It is possible in this way tocompensate the phase and amplitude response generated by the responsecharacteristic of the controlled system which is dependent on adisturbance variable. This produces in a stationary manner a controlsystem without a phase and amplitude response between the setpoint andactual value.

Advantageous process steps include having the setpoint value vector(i_(w)) determined by means of a transformation of the multiphasesetpoint value i_(Rw), i_(Sw), i_(Tw)) into orthogonal setpoint values(i.sub.αw, iβ_(w)), the modulus setpoint value (|i_(w) |) and the rotaryangular setpoint value (ε_(w)) of the setpoint value vector (i_(w))determined form the orthogonal setpoint values (i.sub.αw) by means ofthe following equations ##EQU1## and having the actual value vector(i_(x)) determined by means of a transformation of the multiphase actualvalue (i_(Rx), i_(Sx), i_(Tx)) into orthogonal actual values (i.sub.αx,i.sub.βx), the modulus actual value (|i_(x) |) and the rotary angle(ε_(x)) of the actual value vector (i_(x)) being determined form theorthogonal actual values (i.sub.αs, i.sub.βx) by means of the followingequations ##EQU2## and further having the multiphase compensatedsetpoint value (i_(RKw), i_(SKw), i_(TKw)) determined by means of thefollowing equations ##EQU3## the orthogonal compensated setpoint values(i.sub.αKw, i.sub.βKw) being calculated by means of the followingequations

    i.sub.αkw =|i.sub.Kw |·sinε.sub.Kw

    i.sub.βKw =|i.sub.Kw |·cos ε.sub.Kw

In a circuit arrangement according to the invention for implementing theprocess having a controlled system, to which a multiphase actual valuecan be fed by an actuator and which is compared by means of a comparatorwith a multiphase setpoint value whose multiphase system deviation canbe fed to the actuator via controllers, the multiphase setpoint valuecan be fed to a desired correction value computer at whose furtherinputs the multiphase actual value is present, and this desiredcorrection value computer is connected in an electrically conductivefashion to the comparators.

Advantageous embodiments of the correction value computer includeproviding the input side the desired correction value computer (20) witha setpoint value vector computer (26) whose output and the output of thesetpoint value vector computer (26) are connected on the input side viaadders (46,48) to a second setpoint value computer (30), such that:

1. the setpoint value vector computer (26) contains a resolver (32) anda Cartesian to Polar transformer (34);

2. the actual value vector computer (28) contains a resolver (32) and aCartesian to Polar transformer (34);

3. the second setpoint value computer (30) contains a Polar to Cartesiantransformer (50) and a resolver (52); and

4. the input side the compensation circuit (36) has two differentialelements (38, 40), there being connected downstream of one aproportional integral controller (42) and of the other an integralcontroller (44) whose outputs are connected to the outputs of thecompensation circuit (36).

It is possible by means of this circuit arrangement to compensate anundesired phase and amplitude response between the multiphase setpointand actual value in the stationary state, although the responsecharacteristic of the controlled system is a function of the disturbancevariable.

A particularly advantageous embodiment of this circuit arrangement is amicrocomputer which computes the multiphase compensating setpoint valuefrom the multiphase measured actual value and the input multiphasesetpoint value by means of a computer program, so that an undesiredphase and amplitude response is compensated between the setpoint andactual value.

In order to explain the invention further, reference is made to thedrawings, in which an exemplary embodiment of the circuit arrangementfor implementing the process according to the invention for compensatinga phase and amplitude response between a multiphase setpoint and actualvalue is illustrated diagrammatically.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a multiphase control loop having a circuit arrangement forimplementing the process according to the invention, in

FIG. 2 a block diagram of the circuit arrangement for implementing theprocess according to the invention in accordance with FIG. 1 isrepresented, and

FIGS. 3 to 6 illustrate typical circuits of the individual blocks of theblock diagram of the circuit arrangement according to FIG. 2.

DETAILED DESCRIPTION

Represented in FIG. 1 is a multiphase control loop 2 which consists of aplurality of comparators 4, 6 and 8, a plurality of controllers 10, 12and 14, an actuator 16, a controlled system 18 and a desired correctionvalue computer 20. A conventional current control for a three-phasecurrent drive with a voltage-controlled convertor 22, which is triggeredby a pulse-width modulator 24, is provided as a concrete embodiment ofthis multiphase control loop 2. Current controllers having, for example,a proportional or a proportional-integral response which in each casegenerates a manipulated variable i_(Ry) or i_(Sy) or i_(Ty) from asystem deviation i_(Re) or i_(Se) or i_(Te) are provided as controllers10, 12 and 14. A three-phase current drive to which a multiphase actualvalue i_(Rx), i_(Sx) and i_(Tx) is fed from the actuator 16 is providedas the controlled system 18. The response characteristic of thecontrolled system is also a function of a disturbance variable M_(z),which acts on the drive shaft. A compensated, multiphase setpoint valuei_(Rkw), i_(Skw) and i_(Tkw) is generated with the aid of the multiphaseactual value i_(Rx), i_(Sx) and i_(Tx) from the multiphase setpointvalue i_(Rw), i_(Sw) and i_(Tw) present at the first inputs of thedesired correction value computer 20, which is further explained in moredetail in FIGS. 2 to 6. This compensated, multiphase setpoint valuei_(Rkw), i_(Skw) and i_(Tkw) is compared with the multiphase actualvalue i_(Rx), i_(Sx) and i_(Tx) in correct phase. An undesired phase andamplitude response is obtained in conjunction with rising frequency ofthe setpoint value i_(Rw), i_(Sw) and i_(Tw) between the multiphasesetpoint value i_(Rw), i_(Sw) and i_(Tw) and the multiphase actual valuei_(Rx), i_(Sx) and i_(Tx). The frequency and the amplitude of themultiphase setpoint value i_(Rw), i_(Sw) and i_(Tw), which is injectedinto the controlled system 18 via the controllers 10, 12 and 14 and theactuator 16, is here a function of the desired speed and torque of thepolyphase machine. This undesired phase and amplitude response can becompensated between the multiphase setpoint and actual value i_(Rw),i_(Sw), i_(Tw) and i_(Rx), i_(Sx), i_(Tx) with the aid of the desiredcorrection value computer.

FIG. 2 represents a block diagram of the desired correction valuecomputer 20. Provided on the input side is a setpoint value vectorcomputer 26 and an actual value vector computer 28, and on the outputside a second setpoint value computer 30. A multiphase, preferably athree-phase, setpoint value i_(Rw), i_(Sw) and i_(Tw) is fed to thesetpoint value vector computer 26. This setpoint value vector computer26 contains a resolver 32 and a C/P transformer 34, which are connectedelectrically in series. The resolver 32 transforms the three-phasesystem into an orthogonal system. A circuit embodiment of this resolver32 is represented in more detail in FIG. 3. The outputs of the resolver32 provide two orthogonal setpoint values i.sub.αw and i.sub.βw, whichare transformed by means of the C/P transformer 34 into a modulussetpoint value |i_(w) | and a rotary angular setpoint value ε_(w) of thesetpoint value vector i_(w). That is to say, a Cartesian coordinatesystem is transformed into a polar coordinate system by means of the C/Ptransformer 34. A circuit embodiment of this C/P transformer 34 isrepresented in more detail in FIG. 4.

The actual value vector computer 28 is constructed precisely like thesetpoint value vector computer 26, that is to say with a resolver 32 anda C/P transformer 34. The multiphase, preferably three-phase, actualvalue i_(Rx), i_(Sx) and i_(Tx) is transformed via two orthogonal actualvalues i.sub.αx and i.sub.βx into a modulus actual value |i_(x) | and arotary angular actual value ε_(x) of the actual value vector i^(x) bymeans of these transformers 32 and 34.

Determination of the modulus setpoint value |i_(w) | with associatedrotary angular setpoint value ε_(w) of the setpoint value vector i_(w),and of the modulus actual value |i_(x) | with associated rotary angularactual value ε_(x) of the actual value vector i_(x) can be performed byhardware, as is further explained in more detail in FIGS. 3 and 4, or bysoftware. When determination is done by software, each block 26, 28, 30and 36 of the desired correction value computer 20 is realizedapproximately by a software program, the coordinate transformations onthe input and output sides preferably being realized by hardware, sinceat least the multiphase actual value i_(Rx), i_(Sx) and i_(Tx) an analogvalue.

The outputs of the desired value vector computer 26 and the actual valuevector computer 28 are connected on the input side to a compensationcircuit 36, the modulus setpoint value |i_(w) | and the modulus actualvalue |i_(x) | being connected to a first differential element 38, andthe angular setpoint value ε_(w) and the angular actual value ε_(x)being connected to a second differential element 40. Present at theoutput of the first differential element 38 is a modulus differentialvalue |i_(w) |-|i_(x) |, from which a modulus manipulated variable|i_(wxy) |, which is present at the output of the compensation circuit36, is generated by means of a controller 42. Present at the output ofthe second differential element 40 is an angular differential valueε_(w) -ε_(x), from which an angular manipulated variable ε_(wxy), whichis present at a further output of the compensation circuit 36, isgenerated by means of a further controller 44. A controller acting in aproportional-integral fashion is provided as the controller 42. Acontroller acting in an integral fashion is provided as the controller44. The more the actual value vector i_(x) deviates in modulus and phasefrom the setpoint value vector i_(w), the greater is the modulusmanipulated variable |i_(wxy) | and the angular manipulated variableε_(wxy) at the two outputs of the compensation circuit 36.

The outputs of the setpoint vector computer 26 and the outputs of thecompensation circuit 36 are added in terms of modulus and phase by meansof two adders 46 and 48. A compensated modulus setpoint value |i_(Kw) |is present at the output of the adder 46, and a compensated angularsetpoint value ε_(Kw) is present at the output of the adder 48. Thiscompensated setpoint value vector i_(Kw) it represented by modulus andphase is transformed by means of the second setpoint value computer 30into a three-phase compensated setpoint value i_(RKw), i_(SKw) andi_(TKw).

The second setpoint value computer 30 contains a P/C transformer 50(polar/Cartesian) and a resolver 52, which are connected electrically inseries. On the input side, the setpoint value computer 30 has apolar-Cartesian resolver 50, with which two orthogonal setpoint valuesi.sub.αKw and i.sub.βKw are generated from the modulus value |i_(Kw) |and the angular value ε_(Kw). These orthogonal setpoint values i.sub.αKwand i.sub.βKw are transformed into a three-phased compensated setpointvalue i_(Rkw), i_(Skw) and i_(TKw) by means of the resolver 52. Circuitembodiments of the P/C transformer 50 and of the resolver 52 arerepresented in FIGS. 5 and 6. This second setpoint value computer 30 canalso be realized by software. In this case, an appropriate program isstored as a subprogram in the desired correction value computer 20. Itwould also be advantageous for only the P/C transformer 50 to berealized by software and the resolver 52 by hardware, if the subsequentcontrol is performed digitally or in an analog fashion.

The compensation of the undesired phase and amplitude response betweenthe multiphase setpoint and actual value i_(Rw), i_(Sw), i_(Tw) andi_(Rx), i_(Sx) and i_(Tx), caused by the response characteristic of thecontrolled system 18, which depends on the disturbance variable M_(z)and the frequency of the setpoint value i_(Rw), i_(Sw) and i_(Tw), isachieved with the aid of this desired correction value computer 20.

FIG. 3 represents a circuit arrangement of the resolvers 32 of thedesired correction value computer 20 of FIG. 2. This resolver 32transforms a three-phased system, for example a three-phase setpointvalue i_(Rw), i_(Sw) and i_(Tw) or a three-phase actual value i_(Rx),i_(Sx) and i_(Tx) into an orthogonal system, for example orthogonalsetpoint values i.sub.αw and i.sub.βw or orthogonal actual valuesi.sub.αx and i.sub.βx. The book "Stromrichter zur Drehzahlsteuerung vonDrehfeldmaschinen", (Static convertors for speed control of polyphasemachines), Part III, Convertors, pages 102 to 111, especially pages 105and 106 indicates how a two-phase system having two perpendicularcurrents is formed from two phase currents of a three-phase-system. Theaxes of the two-phase system are aligned in this case such that one axisα coincides with the direction of the current i_(R). With the resolver32 represented here, the three-phase setpoint value or actual valuei_(Rw), i_(Sw), i_(Tw) or i_(Rx), i_(Sx) , i_(Tx) are used for thepurpose of calculation (by software) or determination (by hardware). Theorthogonal setpoint or actual values i.sub.αw, i.sub.βw or i.sub.αx,i.sub.βx are calculated or determined by means of the circuitrepresented in FIG. 3 in accordance with the following equations##EQU4## The factors of the two equations are determined by theresistance of the individual operational amplifiers 54, 56, 58 and 60,only the two operational amplifiers 54 and 56 being employed for thesetpoint or actual value i.sub.αw,x. The operational amplifier 62 or 64,which is connected as an inverter, once again cancels the phase reversalof the operational amplifiers 54 and 56 or 58 and 60. The orthogonalsetpoint or actual values i.sub.αw, i.sub.βw or i.sub.αx, i.sub.βx areobtained at the two outputs.

FIG. 4 shows the C/P transformers 34 as a circuit embodiment. In thiscase, the section of the circuit by means of which the angle ε_(w) orε_(x) of the setpoint or actual value vector i_(w) or i_(x) isdetermined is known from U.S. Pat. No. 4,449,117. This circuitembodiment is a hardware conversion of the two equations ##EQU5## whichcan also be converted by software.

FIG. 5 represents the P/C transformer 50 as a circuit embodiment, bymeans of which polar coordinates |i_(Kw) |, ε_(Kw) are transformed intoCartesian coordinates i.sub.αKw, i.sub.βKw. This transformation isperformed according to the equations:

    i.sub.αKw =|i.sub.Kw |·sin ε.sub.Kw

    i.sub.βKw =|i.sub.Kw |·cos ε.sub.Kw.

These equations have been converted by hardware, it being possible foreach resolver 32, 34, 50 and 52 to be converted by software by means ofa program part of a computer program when a microcomputer is used as thedesired correction value computer 20.

The resolver 52 is represented as a circuit embodiment in FIG. 6. Thisresolver 52 transforms an orthogonal system i.sub.αKw, i.sub.βKw into athree-phase system i_(RKw), i_(SKw) and i_(TKw). In this case, thethree-phase system i_(RKw), i_(SKw) and i_(TKw) is calculated by meansof the following equations ##EQU6##

The circuit embodiment represents only one hardware conversion of thethree equations, only operational amplifiers 66, 68, 70, 72 andresistors being employed for factor formation.

What is claimed is:
 1. A process for compensating a phase and amplituderesponse of a system between a multiphase setpoint and an actual value(i_(Rw), i_(Sw), i_(Tw), and i_(Rx), i_(Sx), i_(Tx)) comprising thefollowing process steps:a) determining a modulus setpoint value (|i_(w)|) and a rotary angular setpoint value (ε_(w)) of a setpoint valuevector (i_(w)) formed from the multiphase setpoint value (i_(Rw),i_(Sw), i_(Tw)); b) determining a modulus actual value (|i_(x) |) and arotary angular actual value (ε_(x)) of an actual value vector (i_(x))formed form the multiphase actual value (i_(Rx), i_(Sx), i_(Tx)); c)comparing the modulus setpoint value (|i_(w) |) with the modulus actualvalue (|i_(x) |) and generating a modulus manipulated variable (|i_(wxy)|) from a modulus differential value (|i_(w) |-|i_(x) |) which, whenadded to the modulus setpoint value (|i_(w) |), produces a compensatingmodulus setpoint value (|i_(Kw) |); d) comparing the rotary angularsetpoint value (ε_(w)) with the rotary angular actual value (ε_(x)) andgenerating an angular setpoint value (ε_(wxy)) from an angulardifferential value (ε_(w) -ε_(x)) which, when added to the angularsetpoint value (ε_(w)), produces a compensating angular setpoint value(ε_(Kw)); e) determining a multiphase compensating setpoint value(i_(RKw), i_(SKw), i_(TKw)) of the compensating setpoint value vector(i_(k) ^(w)) formed from a compensating modulus setpoint value (|i_(Kw)|) and the compensating rotary angular setpoint value (ε_(Kw)); andcompensating the system based on the multiphase compensating setpointvalue determined in step (e).
 2. The process as claimed in claim 1,wherein the setpoint value vector (i_(w)) is determined by means of atransformation of the multiphase setpoint value (i_(Rw), i_(Sw), i_(Tw))into orthogonal setpoint values (i.sub.αw, i.sub.βw), the modulussetpoint value (|i_(w) |) and the rotary angular setpoint value (ε_(w))of the setpoint value vector (i_(w)) being determined from theorthogonal setpoint values (i.sub.αw, i.sub.βw) by means of thefollowing equations ##EQU7##
 3. The process as claimed in claim 1,wherein the actual value vector (i_(x)) is determined by means of atransformation of the multiphase actual value (i_(Rx), i_(Sx), i_(Tx))into orthogonal actual values (i.sub.αx, i.sub.βx), the modulus actualvalue (|i_(x) |) and the rotary angle (ε_(x)) of the actual value vector(i_(x)) being determined from the orthogonal actual values (i.sub.αx,i.sub.βx) by means of the following equations ##EQU8##
 4. The process asclaimed in claim 1, wherein the multiphase compensating setpoint value(i_(RKw), i_(SKw), i_(TKw)) is determined by means of the followingequations ##EQU9## where i.sub.αKw and i.sub.βKw are orthogonalcompensated setpoint values, the orthogonal compensated setpoint values(i.sub.αKw, i.sub.βKw) being calculated by means of the followingequations

    i.sub.αKw =|i.sub.Kw |·sin ε.sub.Kw

    i.sub.βKw =|i.sub.Kw |·cos ε.sub.Kw.


5. A circuit arrangement for implementing a process for controllingsystem whichdetermines a modulus setpoint value (|i_(w) |) and a rotaryangular setpoint value (ε_(w)) of a setpoint value vector (i_(w)) formedfrom a multiphase setpoint value (i_(Rw), i_(Sw), i_(Tw)), determines amodulus actual value (|i_(x) |) and a rotary angular actual value(ε_(x)) of an actual value vector (i_(x)) formed from a multiphaseactual value (i_(Rx), i_(Sx), i_(Tx)), compares the modulus setpointvalue (|i_(w) |) with the modulus actual value (|i_(x) |) and generatesa modulus manipulated variable (|i_(wxy) |) from a modulus differentialvalue (|i_(w) |-|i_(x) |) which, when added to the modulus setpointvalue (|i_(w) |), produces a compensating modulus setpoint value(|i_(Kw) |), compares the rotary angular setpoint value (ε_(w)) with therotary angular actual value (ε_(x)) and generates an angular setpointvalue (ε_(wxy)) from an angular differential value (ε_(w) -ε_(x)) which,when added to the angular setpoint value (ε_(w)), produces acompensating angular setpoint value (ε_(Kw)), and determines amultiphase compensating setpoint value (i_(RKw), i_(SKw), i_(TKw)) ofthe compensating setpoint value vector (i_(k) ^(w)) formed from acompensating modulus setpoint value (|i_(Kw) |) and the compensatingrotary angular setpoint value (ε_(Kw)), comprising: a) an actuator, saidactuatori) having an output coupled with said system and adapted toprovide the multiphase actual value (i_(Rx), i_(Sx), i_(Tx)) to saidsystem, and ii) having an input; b) comparators, each of saidcomparatorsi) having a first input coupled with said output of saidactuator and a second input, ii) adapted to compare the multiphaseactual value (i_(Rx), i_(Sx), i_(Tx)) with a multiphase compensatedsetpoint value (i_(RKw), i_(SKw), i_(TKw)) thereby determining amultiphase system deviation (i_(Re), i_(Se), i_(Te)), and iii) having anoutput adapted to provide the multiphase system deviation (i_(Re),i_(Se), i_(Te)); c) controllers, each of said controllersi) having aninput coupled with the output of one of said comparators and adapted toaccept one of the multiphase system deviation (i_(Re), i_(Se), i_(Te)),and ii) having an output coupled with said input of said actuator andadapted to provide one of a multiphase manipulated variable (i_(Ry),i_(Sy), i_(Ty)) to said actuator; and d) a desired correction valuecomputer, said desired correction value computeri) having a first inputcoupled with said output of said actuator and adapted to accept themultiphase actual values (i_(Rx), i_(Sx), i_(Tx)), a second inputadapted to accept the multiphase setpoint values (i_(Rw), i_(Sw),i_(Tw)), ii) adapted to calculate the multiphase compensated setpointvalues (i_(RKw), i_(SKw), i_(TKw)), and iii) having an output coupledwith said second inputs of said comparators adapted to provide saidmultiphase compensated setpoint values (i_(RKw), i_(SKw), i_(TKw)). 6.The circuit arrangement as claimed in claim 5, wherein said second inputof said desired correction value computer includes a setpoint valuevector computer having an output and said first input of said desiredcorrection value computer includes an actual value vector computerhaving an output, said output of said setpoint value vector computer andsaid output of said actual value vector computer each being coupled witha compensation circuit having an output, said outputs of said setpointvalue vector computer and said compensation circuit and said actualvalue vector computer being coupled with an input of a second setpointvalue computer via adders, said second setpoint value computer having aan output coupled with said output of said desired correction valuecomputer.
 7. The circuit arrangement as claimed in claim 6, wherein thesetpoint value vector computer contains a resolver and a cartesian topolar coordinate transformer.
 8. The circuit arrangement as claimed inclaim 6, wherein the actual value vector computer contains a resolverand a cartesian to polar coordinate transformer.
 9. The circuitarrangement as claimed in claim 6, wherein the second setpoint valuecomputer contains a polar to cartesian coordinate transformer and aresolver.
 10. The circuit arrangement as claimed in claim 6, wherein onthe input side the compensation circuit has two differential elements,there being connected downstream of one a proportional integralcontroller and of the other an integral controller whose outputs areconnected to the output of the compensation circuit.